NEWS

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ncdfCF 0.3.0.9000

• CFData objects can now be written to a netCDF file.
• Method CFData$summarise() summarises the temporal dimension of a data object to a lower resolution, using the specific calendar of the temporal dimension and returns a new CFData object with the summarised data.
• Method CFData$data.table() exports a data object to a data.table.
• CFVariable and CFData classes now have time() method to retrieve the CFTime instance of a "time" axis, if present.
• CFAxis has new coordinates field with which to retrieve the coordinates along the axis.
• New attributes can be defined on any object that supports attributes, or deleted.

ncdfCF 0.3.0 (2025-01-19)

• Function peek_ncdf() returns quick-view information on a netCDF resource.
• String-valued labels for discrete and generic numeric axes are now supported, including multiple label sets per axis. The labels are associated with an axis rather than a data variable (as the CF documents imply) and the axis must be explicitly defined (as the CF documents imply but not explicitly state, and it is missing from the example given).
• Functions makeMemoryGroup(), makeLongitudeAxis() and makeLatitudeAxis() added to create scaffolding for new CF objects.
• NCGroup::unused() method identifies unused NCVariables to aid in finding issues with netCDF resources.
• print() method for NCVariable and NCDimension.
• Method CFObject$fullname added, giving fully-qualified CF object name.
• "Axis" associated with bounds variable is no longer created.
• NASA level-3 binned data (L3b) is now supported.
• Reference to a containing NCGroup moved down to CFObject for CF objects.
• Minor code fixes.
• Documentation extended and formatting fixed, new vignette.

ncdfCF 0.2.1 (2024-10-14)

• NetCDF groups are now fully supported, including traversing group hierarchies with absolute or relative paths.
• All axis types are identified correctly. This includes:
  • Regular coordinate axes (a.k.a. NUG coordinate variables).
  • Discrete axes, even when no coordinate variable is present - an extension to the CF conventions.
  • Parametric vertical axes, but values are not yet computed.
  • Scalar axes, linked to variables through the "coordinates" attribute of the latter.
  • Auxiliary longitude-latitude grids, the horizontal component of the grid of a variable that was not defined as a Cartesian product of latitude and longitude, using the "coordinates" attribute of the variable. When subsetting a data variable, resampling is automatically performed.
  • The four axes that "receive special treatment" by the Conventions each have a separate class to deal with their specific nature: CFAxisLongitude, CFAxisLatitude, CFAxisVertical, and CFAxisTime.
• Bounds are read and interpreted on all axes except the vertical axis, including any auxiliary long-lat grids.
• Information on UDTs is captured in a separate class. This is effectively only supported for the "compound" sub-type, for scalar values only.
• Data is read into the most compact form possible. This saves a significant amount of memory when large integer variables are read as they would remain integers rather than the default numeric type.
• Data is returned from CFVariable$subset() as an instance of the CFData class, with associated objects such as axes and the attributes from the variable. Data can be read out in a variety of forms, currently as a raw array, an oriented array or as a terra::SpatRaster or terra::SpatRasterDataset.
• Full support for grid mapping variables. As a significant extension over CF Metadata requirements, CRS strings are produced in the OGC WKT2 format, using the latest EPSG database of geodetic objects.
• Improvements in printing object details.
• Code refactored to R6.
• GHA enabled

ncdfCF 0.1.1 (2024-06-10)

• objects_by_standard_name() will list objects in the netCDF resource that have a "standard_name" attribute.

ncdfCF 0.1.0

• Initial CRAN submission. This is a WORK IN PROGRESS and the package is not yet fit for a production environment.
• This version supports reading from netCDF resources. CF Metadata Conventions are used to set properties on axis orientation, time dimensions and bounds.
• Standard R commands can be used to inspect properties of the netCDF resource, such as dimnames() and length().
• Access to data uses the R standard [ selection operator for use with dimension indices. Use real-world coordinates with subset().